One task often associated with earthwork construction projects relates to capturing soil at one location and depositing the soil at another location. The purpose of this soil movement is often to adjust elevations at different locations within a project area to some predetermined topography. Although this movement of soil can be accomplished in a variety of ways, one particular machine has demonstrated an ability to perform this earth moving task with particular efficiency. These machines are often referred to as scrapers, and typically come in the form of a machine that is pulled by a tractor, which may either be wheel or track type. While many scrapers are simply pulled by a tractor, some provide their own traction via a separate engine that applies rim pull to the wheels of the scraper. Thus, in some instances, the scraper is both pulled by a tractor and pushed through the soil via the wheels of the scraper, analogous to a four wheel drive vehicle. The scraper may also be pushed by a separate machine, such as by a track type tractor.
A typical scraper includes a bowl within which the soil is captured, and a cutting edge located adjacent a cut opening of the bowl. A depth of the cutting edge in the soil is typically set via an actuator that adjusts a pivot position of the bowl about an axle of the machine, but other strategies via raising and lowering the axle are also known. As the scraper is pulled forward, the cutting edge cuts through the soil with a cutting edge oriented perpendicular to the direction of travel, and guides the soil into the bowl. When the bowl is filled to some desired capacity, the bowl is pivoted up so that the cutting edge is out of contact with the soil, and the machine is transported to a deposit location where the soil is deposited. After depositing the soil, the scraper is typically returned to the soil capturing location to retrieve another load, and the duty cycle is repeated.
A typical cutting edge for a scraper is oriented perpendicular to a direction of travel of the machine, and typically extends across the width of the bowl. Some scrapers are also equipped with a so called stinger bit that provides a forward protrusion to the cutting edge across a central portion of a fraction of the bowl width. Such a structure is shown, for example, in U.S. Pat. No. 3,736,664. The stinger bit structure allows the operator to select from the full cutting width by engaging the entire cutting edge with the soil, or a reduced cutting width corresponding to the width of the stinger bit when the bowl is pivoted upward to decrease the engagement of the cutting edge with the underlying soil. As the bowl approaches its filled capacity with soil, an operator may pivot up the bowl to reduce the cutting edge to the width of the stinger bit to continue filling the bowl to its capacity before transporting the soil to a deposit location. This strategy is often utilized as it becomes increasingly difficult to urge more soil into a partially filled bowl as the capacity of the bowl is approached. Although a soil capture and transport strategy using a scraper in a duty cycle as previously described has performed well for many years, there remains room for improvement. In other words, there is constant pressure to improve efficiency by both reducing the energy required to fill a bowl to its desired capacity as well as reducing the time necessary for a single work cycle to capture, transport soil, deposit soil and return for another load.
The present disclosure is directed to one or more of the problems set forth above.